I'm a new firebird owner (an '89 305), and i'm trying to learn the in's an outs of this car.

I'm noticing a distinct difference between the "Regular" and "Premium" grades of gasoline. My engine pings a lot duing acceleration when i'm running 87' octane. But rus well (with some occasional pinging) running 92 octane. Is this typical of the car? Is there something I can do to get it to run better on 87?

I've recently replaced, pulgs, wires, distributor cap + rotor. I've had the car on a smoke machine and there arn't any apparent vacume leaks.

 

You can fiddle with the timing to get some of the pinging to go away.

 

Are you talking about on-ramp like acceleration, or wide-open throttle?

It should run on 87 octane, unless something has been modified. You should make sure the timing is set where it belongs first. If it is pinging at part-throttle acceleration, you may have an EGR valve problem (either valve not operating, or plugged up EGR passages). May also have a knock sensor problem.

 

Yeah, I checked the EGR valve it looks pretty new (I just got this car 2 weeks ago, my first f-body)

I think the problem is, The mechanic performed the tune up (even though i didn't want them to! I just wanted a fuel pump!) and I had a tank of premium when the new distributor cap and rotor were put on. I think they may have adjusted the timing for premium.

I'll take a look at the knock sensor though.

 

The pinging is most likely a timing issue. When the timeing is advanced to a certain degree it will ping. Higher Octane helps the pinging when you are close to your timing limit. Stock your base should be about 6 degrees (don't forget when checking timing to disconnect the computer link at the firewall). You have base timing then the computer typically handles any timing adjustments. If you have an aftermarket chip such as Jet, Hyypertech etc. mainly what they do is increase timing map, so you might want to check to see if you have the stock chip also.

 

Yeah the car is pretty much bone stock from what I can tell.

So you change the timing by adjusting the distributor? (remembering to mark it first of course). Besides disconnecting the chip, anything else i should look out for?

 

i would call the guy n ask if the internals were changed (heads, pistons, if so, whats the compression?)

Disconnecting the chip if its stock wont get you very far, just see if its an aftermarket chip..

to adjust timing you will need to turn the cap, but you wont get any better of solving this problem unless you adjust it to the proper timing.. to do so, you'll need a timing light and disconnect the EST wire (you'll set the base timing, the computer will control the rest of the timing, and you'll want to adjust it between 8-10 degrees, whatever feels better for the engine)

kudos

 

As the above post said you don't need to disconnect your chip just see if its stock (if its aftermarket there will be a brand name on it). Its in you ECM under the dash. Its the wire at the firewall that you need to disconnect to adjust or check your base timing. If you have never done any of this your probably best of getting a book. I mean "the wire at the firewall is pretty vague to work off) Hope this helped.

 

They actually did a compression test, it got great compression numbers.. between 180 and 190 on all cylinders... pretty amazing for an engine with 178,000 miles on it.

I think my father-in law has the timing light stuff, i'll have to call him and find out.

 

wire by the firewall = EST wire

as i said is how your suppose to set the base timing as the BASE timing is the only thing u need to wrory about

no use in buying a book for that... Do a search here, i've seen pictures of it (vader if your reading this, i know u have a picture of it) but its the only wire (brown color I think) above the blower motor on passenger side of the firewall coming out of the main harness, you'll see it.

get a timing gun, disconnect that, set to 8-10 and your set.

 

Is this my EST bypass connector? It's a brown wire and seems to match the discriptions here. Just looking for some confirmation... (Can't be too careful on you're first time)

 

Thats it, make sure the engine is at full operating temp before setting the timing.

 

Ok, I redid the timing on my engine and that was the problem.

When i first started the timing mark on the harmonic balancer was way off out over the 12* marker, but because I read a bunch of posts on the forums, I knew this was expected when the EST wire was still connected. However, after I disconnected the EST wire the timing mark settled exactly on 12*. I guess the guys who did my timing didn't know which point was the 0* mark so they just picked the one that looked right.

The timing marks were all rusted over so there was no way to tell which ones were what. However another quick forum search revealed a diagram showing what the timing marks meant.

The car is running great now, I may adjust the timing ahead to 4-6 later and see how it goes, i just felt like running stock for a while.

One thing that's really handy when you do this job is a Distributor Clamp Wrench; it's really hard to reach the bolt that holds on the distributor on. I went and picked one up from schucks, cost about $8. Well worth the price if you are thinking of messing with your timing.

Oh, and just incase someone is doing a search on this and needs the info, the #1 cylinder on the engine is the closest to the front bumper on the drivers side.